I think Facebook already have our personal information, supplying our kyc documents is only to double check it with our Facebook profiles.
The coin will succeed since Facebook is a trusted platform.
No, there are a lot of profile in FB are fake profile. KYC with Facebook platform is not trust. The only way I think good for ICO project in KYC is submitting passport, national ID and the selfie photo of yourself, it is secure for the ICO members and investors if they buy coins.